Data_Sheet_1_Selective isolation of Arctic marine actinobacteria and a down-scaled fermentation and extraction strategy for identifying bioactive compounds.docx

Actinobacteria are among the most prolific producers of bioactive secondary metabolites. In order to collect Arctic marine bacteria for the discovery of new bioactive metabolites, actinobacteria were selectively isolated during a research cruise in the Greenland Sea, Norwegian Sea and the Barents Sea. In the frame of the isolation campaign, it was investigated how different sample treatments, isolation media and sample-sources, such as animals and sediments, affected the yield of actinobacterial isolates to aid further isolation campaigns. Special attention was given to sediments, where we expected spores of spore forming bacteria to enrich. Beside actinobacteria a high share of bacilli was obtained which was not desired. An experimental protocol for down-scaled cultivation and extraction was tested and compared with an established low-throughput cultivation and extraction protocol. The heat-shock method proved suitable to enrich spore-, or endospore forming bacteria such as bacilli. Finally, a group bioactive compounds could be tentatively identified using UHPLC–MS/MS analysis of the active fractions.</p

Metabolomic Profiling Reveals the <i>N</i>‑Acyl-Taurine Geodiataurine in Extracts from the Marine Sponge <i>Geodia macandrewii</i> (Bowerbank)

A metabolomic approach was used to identify known and new natural products from the marine sponges <i>Geodia baretti</i> and <i>G. macandrewii</i>. <i>G. baretti</i> is known to produce bioactive natural products such as barettin (<b>1</b>), 8,9-dihydrobarettin (<b>2</b>), and bromobenzisoxazolone barettin (<b>3</b>), while secondary metabolites from <i>G. macandrewii</i> are not reported in the literature. Specimens of the two sponges were collected from different sites along the coast of Norway, and their extracts were analyzed using UHPLC-HR-MS. Metabolomic analyses revealed that extracts from both species contained barettin (<b>1</b>) and 8,9-dihydrobarettin (<b>2</b>), and all samples of <i>G. baretti</i> contained higher amounts of both compounds compared to <i>G. macandrewii</i>. The analysis of the MS data also revealed that samples of <i>G. macandrewii</i> contained a compound that was not present in any of the <i>G. baretti</i> samples. This new compound was isolated and identified as the <i>N</i>-acyl-taurine geodiataurine (<b>4</b>), and it was tested for antioxidant, anticancer, and antibacterial properties

Securamine Derivatives from the Arctic Bryozoan <i>Securiflustra securifrons</i>

Bryozoans belonging to the Flustridae family have proven to be a rich source of structurally unique secondary metabolites. As part of our continuing search for bioactive secondary metabolites from Arctic marine invertebrates, the organic extract of <i>Securiflustra securifrons</i> was examined. This resulted in the isolation of three new halogenated, hexacyclic indole-imidazole alkaloids, securamines H–J (<b>1</b>–<b>3</b>), together with the previously reported compounds securamines C (<b>4</b>) and E (<b>5</b>). The structures of the new compounds were elucidated by spectroscopic methods including 1D and 2D NMR and analysis of HRMS data. Through NMR and HRMS analysis, we were also able to prove that <b>1</b>, <b>2</b>, <b>4</b>, and <b>5</b>, when dissolved in MeOH, were converted into their corresponding artifacts, the securamine MeOH adducts <b>m1</b>, <b>m2</b>, <b>m4</b>, and <b>m5</b>. When redissolved in a non-nucleophilic solvent, the native variants were re-formed. We also found that <b>3</b> was a MeOH addition product of a native variant. Even though the structures of several securamines have been reported, their bioactivities were not examined. The securamines displayed various degrees of cytotoxicity against the human cancer cell lines A2058 (skin), HT-29 (colon), and MCF-7 (breast), as well as against nonmalignant human MRC-5 lung fibroblasts. Compounds <b>1</b>, <b>2</b>, and <b>5</b> were found to be active, with IC₅₀ values against the cancer cell lines ranging from 1.4 ± 0.1 to 10 ± 1 μM. The cytotoxicity of <b>1</b> was further evaluated and found to be time-dependent

Data_Sheet_1_Four new suomilides isolated from the cyanobacterium Nostoc sp. KVJ20 and proposal of their biosynthetic origin.pdf

The suomilide and the banyasides are highly modified and functionalized non-ribosomal peptides produced by cyanobacteria of the order Nostocales. These compound classes share several substructures, including a complex azabicyclononane core, which was previously assumed to be derived from the amino acid tyrosine. In our study we were able to isolate and determine the structures of four suomilides, named suomilide B – E (1–4). The compounds differ from the previously isolated suomilide A by the functionalization of the glycosyl group. Compounds 1–4 were assayed for anti-proliferative, anti-biofilm and anti-bacterial activities, but no significant activity was detected. The sequenced genome of the producer organism Nostoc sp. KVJ20 enabled us to propose a biosynthetic gene cluster for suomilides. Our findings indicated that the azabicyclononane core of the suomilides is derived from prephenate and is most likely incorporated by a proline specific non-ribosomal peptide synthetase-unit.</p

Isolation and Synthesis of Pulmonarins A and B, Acetylcholinesterase Inhibitors from the Colonial Ascidian <i>Synoicum pulmonaria</i>

Pulmonarins A and B are two new dibrominated marine acetylcholinesterase inhibitors that were isolated and characterized from the sub-Arctic ascidian <i>Synoicum pulmonaria</i> collected off the Norwegian coast. The structures of natural pulmonarins A and B were tentatively elucidated by spectroscopic methods and later verified by comparison with synthetically prepared material. Both pulmonarins A and B displayed reversible, noncompetitive acetylcholinesterase inhibition comparable to several known natural acetylcholinesterase inhibitiors. Pulmonarin B was the strongest inhibitor, with an inhibition constant (<i>K</i>_i) of 20 μM. In addition to reversible, noncompetitive acetylcholinesterase inhibition, the compounds displayed weak antibacterial activity but no cytotoxicity or other investigated bioactivities